INCLUDE "H6:SIEVE.ACT"

CARD FUNC SumDivisors(CARD x)
  CARD i,max,sum

  sum=1 i=2 max=x
  WHILE i<max
  DO
    IF x MOD i=0 THEN
      max=x/i
      IF i<max THEN
        sum==+i+max
      ELSEIF i=max THEN
        sum==+i
      FI
    FI
    i==+1
  OD
RETURN (sum)

PROC Main()
  DEFINE MAXNUM="20000"
  BYTE ARRAY primes(MAXNUM+1)
  CARD m,n

  Put(125) PutE() ;clear the screen
  Sieve(primes,MAXNUM+1)
  FOR m=1 TO MAXNUM-1
  DO
    IF primes(m)=0 THEN
      n=SumDivisors(m)
      IF n<MAXNUM AND primes(n)=0 AND n>m THEN
        IF m=SumDivisors(n) THEN
          PrintF("%U %U%E",m,n)
        FI
      FI
    FI
  OD
RETURN